The long-term objective of this project is to apply the technique of resonant Raman scattering as a probe of active-site structure of heme proteins in solution. For the coming year our proposed work includes: 1) continuation of low temperature Raman studies of heme proteins, with emphasis on the trapping of unstable species, 2) extension of our initial Soret-band resonant Raman studies using tunable ultraviolet lasers, 3) initiation of a study of Raman polarization in oriented single crystals of myoglobin and hemoglobin, and 4) exploratory Raman measurements of unusual heme proteins.